Amongst others, due to their long lifetime and high energy efficiency, solid state LED sources are swiftly replacing traditional incandescent bulb and fluorescent Tube Light, TL, lamps in both private and industrial lighting applications, including warehouses, shops, stores, schools, factories and the like. To take advantage of solid state lighting in traditional lighting applications and systems, so-called solid-state or LED retrofit lighting devices are provided. A solid-state retrofit lamp is typically adapted to fit into the socket of a traditional lamp fixture to be retrofitted. In practice, LED retrofit lighting devices are available for readily any type of traditional or legacy fixture.
Present building lighting management systems, BMS, necessitate a transition of traditional lighting systems comprised of isolated lighting devices or groups of lighting devices, commonly operated by a single switch or switching device, into intelligent, networked and communicatively connected lighting systems.
For an economical replacement of traditional light sources by LED lamps or LED lighting modules on a large scale, dedicated luminaire such as TL luminaires or fixtures, for example, need to be modified as less as possible.
In practice, this means that the wiring and control circuits, such as an electromagnetic, EM, ballast in a fluorescent lighting fixture are not to be removed or altered, and that just the tube lamp or bulb is to be replaced by a solid state retrofit lighting device.
For a proper operation and light management of retrofit light sources, plural system parameters are required, among which the type of ballast already installed in a legacy luminaire or fixture, for example.
Determining the type of ballast via manual inspection of each luminaire is economically hardly feasible, or may even not be possible because the luminaire housing cannot be opened without breaking seals or impacting a safety label or the like.
Published United States patent application US2013/0320869 discloses a light emitting diode tube lamp, TLED, arranged for detecting the type of EM ballast, from electrical current measurements performed and evaluated by a ballast type detection algorithm implemented in a processor controlled driver integrated in the housing of the TLED lamp.
Published United States patent application US2016/0165687 discloses a ballast type detecting circuit from frequency measurements.
Both prior art applications are arranged to control the supply voltage in a particular luminaire for operating a retrofit LED light source or lamp in accordance with the detected type of ballast.
Cost efficient maintenance and high reliability are key performance indicators in industrial lighting systems. In case of malfunctioning of a ballast, for example, for efficient and quick repair and to keep the costs of spare parts as low as possible, service personnel should be informed in advance of the type of ballast installed in a particular luminaire. In particular when a selected type of LED light source or lamp is installed adapted to a particular type of ballast or when plural LED light sources or modules connect to a common ballast, for example.